Evaporator for freezer mechanisms



Nov. 3, 1959 L. E. BRANcHFLowER 2,910,841

EVAPORATOR FOR FREEZER MECHANISMS 5 Sheets-Sheet 1 Original Filed Feb.8, 1951 INVENTOR.

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EVAPORATOR FOR FREEZER MECHANISMS Original Filed Feb. 8. 1951 5Sheets-Sheet 2 (2 y/e E. Branc/)flower ATTORNEY Nov. 3, 1959 L. E.BRANcHFLowER 2,910,841

EvAPoRAToR FOR FREEZER MEcHANsMs 5 Sheets-Sheet 5' Original Filed Feb.8. 195i JNVENTOR. gy/e f. rancf/ower ATTORNEY Nov. 3, 1959 E.BRANcHFLowER 2,910,841

EVAPORATOR FOR FREEZER MECHANISMS 5 Sheets-Sheet 4 Original Filed Feb.8. 1951 l Il lilll l l INVENTOR. y/e E. Bran B1. M f

eg f/o yer TTO/VEY Nov. 3, 1959 L. E. BRANcHFLowER 2,910,841

EVAPORATOR FOR F'RE'EZERv MECHANISMS 5 Sheets-Sheet 5 Original FiledFeb. 8, 1951 JNVENToR. Ly/e E. rdncf/ower BY v W X72??? United StatesPatent Ofice EVAPORATOR FOR FREEZER MECHANISMS Lyle E. Branchllower,Seattle, Wash.

Original application February 8, 1951, Serial No. 210,030. Divided andthis application August 3, 1954, Serial No. 447,576

4 Claims. (Cl. 62-347) The present invention relates to ice makingmachines and the art thereof and is a divisional application of myco-pending application, Serial No. 210,030, led in the United StatesPatent Office on February 8, 1951, now Patent No. 2,735,275.

While devices of my invention herein are useful in vertical orhorizontal ice makers, the invention of the present invention has itsgreatest utility in connection with ice forming on a horizontal surfaceand thus the invention is defined and described in associationtherewith.

The present invention relates to devices and processes for removal ofice having a temperature in the order of 32 F. and removing the ice inchip or particle form.

The prior art has recognized the problem of obtaining velocity to therefrigerant over the heat transfer surface to increase the heattransfer, to prevent the formation of gas pockets, and to reduce theaccumulation of oil on the heat transfer surfaces. However, all of theprior art devices have the defect that velocity is attained by a loss ofhead and by a single pass of the refrigerant across the heat transfersurface. In these devices the velocity must be controlled by the rate ofevaporation of the refrigerant or much wet refrigerant must be returnedto the compression cycle. Further, such devices do not provide forefllcient separation of the gas from the liquid. Separation must occurin the machine which means that some of the heat transfer surface mustbe contacted by gas only and not liquid refrigerant. This means a lowrate of heat transfer for these gas contacted areas.

An object of the present invention is the provision of La gas separatorand liquid return for the refrigerant.

Another object is the provision of means for cycling liquid refrigerantacross the heat transfer surfaces without the passing of suchrefrigerant to the compression unit.

Another object is the provision of refrigerant cycling means to obtain ahigh refrigerant velocity across the heat transfer surfaces, and whichmeans operates as a combined thermosiphon and gas pump.

A further object is the provision of a gas separation space outside ofthe refrigerant evaporator.

Exterior of and concentric of the sleeve on which ice is formed is anannular refrigerant chamber, or evaporator chamber, which is floodedwith a liquid refrigerant. The chamber is divided by an annular bailleinto two annular spaces that are in communication at the top and bottomof the spaces. The liquid level is maintained at or near the top of thebaille. Liquid and gas will rise in the inner space and liquid aloneflows downward in the outer space. Gas and entrained liquid are carriedout of the top of the annular space to a gas separator from which theliquid returns to the outer annular space and the gas goes to acompressor.

The incoming refrigerant is expanded before reaching the evaporator andplaced in heat exchange relationship with the incoming high pressurerefrigerant to precool the refrigerant.

Other objects and advantages of my invention will become apparent as thedescription of the same proceeds Patented Nov. 3, 1959 and the inventionwill be best understood from a consideration of the following detaileddescription taken in connection with the accompanying drawings forming apart of the specification with the understanding, however, that theinvention is not to be limited to the exact details of constructionshown and described since obvious modifications will occur to a personskilled in the art.

Figure l is a perspective view of an assembled machine with partsthereof broken away of a device embodying my invention;

Fig. 2 is a sectional elevation view on the diameter of the machine;

Fig. 3 is a plan view of the device shown in Fig. 1;

Fig. 4 is a transverse sectional plan view on the line 4 4 of Fig. 2;

Fig. 5 is a transverse sectional plan view on the line 5-5 of Fig. 2;

Fig. 6 is a plan View of the water feed ring.

Fig. 7 is an enlarged view of a portion of the ring shown in Fig. 6;

Fig. 8 is a section on the line 8 8 of Fig. 7.

Fig, 9 is a detail view in perspective of two of the ice sweeps;

Fig. 10 is a detail View in perspective of a portion of the doctor bladeand guard;

Fig. 11 is a detail view in perspective of the top edge scraper;

Fig. 12 is a detail view in perspective of the bottom edge scraper andthe water trough guard.

In the accompanying drawings, there is shown in Figure 1 a perspectiveview of an assembled flake ice machine. Parts of the machine are shownbroken away for clarity of understanding. In this view ther is shown theice making machine mounted on the top of an ice storage bin 2 (shown inpart only). The machine has as its principal parts a refrigerantprecooler 3, a gas separation chamber 4, an annular evaporator 5, a basering assembly 6, a top ring assembly 7, and a rotor assembly 8.

Evaporator The evaporator is composed of an upright inner cylindricalshell 10 upon the inner, or ice making surface 11, on which is formedthe thin sheet of ice to be removed therefrom in the form of smallflakes; an outer shell 12 concentric of the inner shell and spacedoutwardly therefrom; a top end closure annulus 13; a bottom end closureannulus 14; and between said shells an annular circulation baille 15that extends circumferentially and longitudinally of the annularevaporation chamber formed by said shells and end annuli, or rings, butis spaced from the ends and shells. The present evaporator is to beoperated in a ilooded condition with the refrigerant 16, preferablyammonia, ilooding over the top of the circulation baflle 15. Refrigerantis delivered from the pre-cooler 3 to the interior of the evaporator byway of the separator 4 thru a refrigerant inlet 17 (see Figs. 2 and 4)formed in the lower part of the separator 4 and refrigerant is removedfrom the evaporator to the separator 4 thru a refrigerant outlet opening18 formed in the outer shell 12 adjacent-the top edge thereof. An inletopening 20 is provided in the shell 12 for the return of liquidrefrigerant from the separator 4. In actual use the outside of the outershell 12 is covered with insulation which has not been shown in thedrawings as such would only confuse the showing thereof. Also, in actualuse, the pre-cooler and the separator would be covered with insulation.

Top and bottom rings The evaporator is set on the base ring 6 thatcarries on its interior and circumferentially thereof a water troughthat opens upwardly and is formed by the outer trough and base ring `21,the inner trough ring 22 spaced inwardly from the outer ring, and thetrough bottom annulus 23. The inner ring 22 has a slightly smallerdiameter than the inner shell 10 of the evaporator. Water collects inthe trough from the excess water running off the lower edge of the icemaking surface 11 and from overflow from the water feed overflowchamber. Water in the trough is drained therefrom thru trough drainopening 24 formed in the base ring 21. Spider arms 25, 26 are securedradially of the rings 21, 22 to support at the axis of the evaporator aradial-thrust bearing 27.

Set on the evaporator is a top ring assembly 7 that is composed of thecylindrical ring 28 that has spider arms 29, 30, 31 (see Fig. 3) securedradially thereof to support at the axis of the evaporator aradial-thrust bearing 32 (see Fig. 2). The annular opening thru the topring may be closed by fixed annular closure plate 33 and removable onessimilar to the fixed ones but not shown in the drawings.

Rotor assembly There is only one moving assembly in the machine. Thisrotor assembly 8 is driven by a gear head motor 40 that is mounted onthe fixed closure plate 33 in the top ring assembly 7. This motor drivesa pinion 41 that meshes with a gear 42 secured to and coaxial of acomposite shaft having a top section 43 to which the gear 42 is secured,and a bottom section 44. In the present disclosure, in plan view, theshaft has counter clock rotation. Secured to the bottom section of theshaft are upper and lower shaft arms 45, 46. These arms carry a sweeprail 47 that is rectangular in cross-section, that extends from the topedge to the lower edge of the evaporator and that is placed close to theice making surface 11 of the evaporator with its side opposed to suchsurface.

Secured to the side of the rail in opposition to the ice freezingsurface are a series of sweeps 48. Each sweep (Figs. 4 and 9) issomewhat in the form of a flat plate having one edge secured to a sweepbase 48A fastened to the side of the rail 47 opposed to the ice surface11. Each sweep extends away from its base and the rail, and past thetrailing edge of the rail. The trailing portion 49 of the sweep may besaid to have rake with respect to the rail 47. This trailing, or rake,portion has a sharp edge 50 in opposition to the freezing surface. Thisedge is obtained by beveling the top of the rake to leave or form theedge in the plane of the lower face of the rake. The sweep and this rakeedge are at a slight angle, about 4 to to a plane normal to the axis ofthe freezing surface. In a machine in which the radius of the freezingsurface is about two feet or more, the rake edge 50 may lie in a plane,but in smaller machines the edge would approach the form of a portion ofa cylindrical helix whose diameter is that of the diameter of thefreezing surface.

As a specific example, if the radius of the freezing surface is twentyinches, the rake edge 50 is two and onefourth inches long, lies in aplane, and is curved to a radius of twenty inches. The trailing end ofthe rake edge is seven-thirtyseconds of an inch below the leading end ofthe edge. This slope of the rake edge sweeps the ice from the icesurface 11. The sweeps are spaced about one and one-half inches apart.All or most of the rake portion of the sweep trails the sweep rail. Thesweeps may be secured to the rail by welding, bolting, or keying.

The angle that the rake edge makes with a plane normal to the axis ofthe evaporator may be considered to be the angle of lead, or the lead,as in a screw thread. This angle, or lead, is critical as too great alead will cause the ice to powder and too small a lead will not effectsatisfactory ice removal as to quantity. Under proper shaping andlocation of the rake edge, and with Dry Ice about one-eighth to onesixteenth inches thick, the ice removal at each passage of the sweeps isin the order of ninety-eight percent complete. Also, with this shapingof the rake and its edge, all the forces exerted on the ice by the sweepare parallel, or tangential, to the surface of the ice, except for suchforces as may result at the forward end of the rake edge where it entersthe ice. There is no force component where sweep and ice contact that isnormal to the ice freezing surface. Such a normal force causes the iceto powder along the rake edge with the result that forces are nottransmitted thru the ice for any distance suiiicient to loosen the icebetween adjacent sweeps. This results in such or most of the ice beingleft on the freezing surface until a very thick layer is built up, asafter several passages of the sweeps.

Frost builds up on the end annuli 13, 14 and will extend inwardly beyondthe ice making surface 11. This frost is scraped back llush with thesurface 11 by upper and lower Scrapers 51 and 52 (Figs. ll and 12) whichare secured by arms to the upper and lower end, respectively, of thesweep rail 47, and which Scrapers have their scraping edges adjacent andoverhanging the ends of the freezing surface.

Also, carried at the lower end of the sweep rail 47 is a trough guard S3(Fig. l2) that prevents ice falling from the sweeps from entering thetrough formed in the base ring assembly 6. Any ice hitting the guardwill be deflected inside of the inner trough ring 22 (Fig. 2) and willfall into the bin 2. The sweep rail 47 carries outboard of its trailingedge a rubber doctor blade 54 (Fig. 10) and blade guard 55 that extendfrom the top to the bottom edge of the evaporator. This doctor blade andguard prevent scattering of the ice coming from the sweeps, and theblade removes loose ice that might adhere to the ice freezing face 11.The doctor blade and guard are secured to the sweep rail by bent straps56.

Water system Water is delivered to the freezing surface 11 by a waterrecycle pipe 60 (Fig. 2) that empties into the upper end of the hollowtop section 43 of the composite shaft. The lower end of this top sectionis closed by a plug 61 which has extending therethrough a short lengthof overflow pipe 62 whose upper end is somewhat above the plug. Watercollecting above the plug is carried away thru nozzle ring pipes 63, 64(Fig. 4) to a nozzle ring 65 that is concentric of the evaporator,adjacent the upper edge of the freezing surface, and carried on nozzlering arms 66 secured to and radially of the upper end of the bottomsection 44 of the shaft. The nozzle ring 65 is hollow, square in crosssection and has around its lower outer edge a series of orifices 67, ornozzles, that are shaped to direct streams of water outwardly,downwardly and circumferentially in the direction of rotation andagainst the ice forming surface 11. This directing of the water againstand circumferentially of the ice forming surface spreads the water overthe surface and prevents its channeling. It, also, gives immediatecoverage with water at the top of the freezing surface. The nozzle ringis segmental for about 270 from immediately behind the doctor blade 54and its guard 55. In this relationship, the doctor blade and guardprevent water from reaching the falling ice. The ninety degrees of thenozzle ring that is open allows the ice time in which to dry and to beremoved. The water delivered thru the ring is maintained constant byholding a fixed pressure, or head, on the ring. This is accomplished bythe use of the overflow pipe 62 and by maintaining during operation ofthe machine a flow thru the overflow to compensate for variations in theamount of water delivered to the top section 43. The overflow waterpasses thru the overflow pipe 62 and into the top of the bottom section44 where it is stopped by a plug 68 (Fig. 2). A drain pipe 69 leads fromabove the plug 68 to the water collecting trough in the base ringassembly 6. This drain pipe 69 is secured to the rotor assembly 8 andmoves around with it.

Water from the collecting trough flows from the outlet 24 to a watersump 70. Water from the sump is returned to the spray ring 65 by thefeed pipe 60 in which is connected a water pump 71, driven by anysuitable means. Make-up water is supplied from a water main 72 to thesump 70, and its flow into the sump is controlled by a water float valve73.

Precooler The precooler 3 comprises a vessel 80 (Figs. l and 2)connected to the refrigerant inlet opening 17 of the separator 4. Highpressure refrigerant such as liquid ammonia from the recevier of acompression system is delivered thru a supply pipe 81 to a heatexchanger where it is cooled between an outer jacket 82 and an innerjacket 83 thereof. These jackets may be finned in any suitable manner.The exchanger is located inside of the vessel 80. Refrigerant, cooled tonear zero degrees Fahrenheit between the jackets, passes thru passageway82 in the lower end of the heat exchanger and into the bottom of thevessel 80. Refrigerant is drawn off the top of the vessel thru a pipe 85leading to an expansion valve 86 thru which the refrigerant is expandedto a lower pressure and returned by the pipe 85 to the inside of theinner jacket 83 of the heat exchanger. Passage thru the expansion valvereduces the temperature of the refrigerant so that in passing thru theexchanger it will cool the high pressure incoming liquid. Liquidrefrigerant and gas from the exchanger is conducted to the separatorthru a pipe 87 connected between the exchanger and the inlet opening 17of the separator.

Separator Gas and entrained liquid from the evaporator pass from the topof the evaporator thru the outlet opening 18 to the gas separationchamber 4. The chamber is in the form of a closed upright separationtube 90 (Fig. l) having an inlet 9i (Fig. 2) in the side near the bottomconnecting with the evaporator outlet 18, a liquid return opening 92 inthe bottom of the separator connecting with the evaporator liquid returnopening 20, and a gas outlet 93 in its side near the top which connectswith the compression system which has not been shown but may be of anystandard and suitable type. The cross sectional free area of theseparator tube 90 is such that the rate of fall of the liquid particlesin the gas stream rising in and thru the separation chamber will begreater than the upward velocity of such gas stream. A baffle 94 infront of the inlet 9i prevents short circuiting of the wet vapor fromthe evaporator to the gas outlet 93 and gives the incoming vapor ahelical movement `which aids in the gas-liquid separation.

Operation ln the operation of the present device, the motor 40 foroperation of the rotor assembly is energized to rotate the shaft a3, 44;water is supplied to the sump 70 from the water main 72, its level inthe sump is controlled by the float 73, and this water is circulatedover the ice making surface 11 by the circulating water pump 71 and itsassociated piping including the nozzle ring 65; refrigerant such asliquid ammonia is supplied from the high side of a compression system tothe precooler 3, thence, thru the separator 4 to the evaporator 5, andthe Vapor from the evaporator has the entrained liquid separated out inthe separator l and returned to the compression system.

When the temperature of the freezing surface 11 falls to and below thefreezing point of water, ice `will form on the surface. The open gap inthe water nozzle ring 65 provides a period during which water is notapplied to a portion of the ice surface which allows the ice to dry,harden, and sub-cool. This Dry Ice is swept from the freezing surface bythe sweeps 48 and cascades down along the doctor blade 54 and its guard55 to fall 1nto the bin 2. Ice does not tend to lodge and pack betweenthe sweeps becanse the rake portion of the sweeps trails the rail uponwhich the sweeps are mounted. Ice is prevented from falling in the watertrough by the trough guard 53.

A high rate of heat transfer is promoted by the rapid circulation of therefrigerant across the surface of the shell 10. This is accomplished bythe circulation batlle 15 forming an ascending passage and a descendingpassage between the inner shell 10 and the outer shell 12 of theevaporator 5. Heat delivered to the refrigerant in the ascending passageand the gas formed in 'this passage induces an upward circulation of therefrigerant in the ascending passage and a downward current in thedescending passage. Gas and entrained liquid are drawn off the top ofthe refrigerant adjacent the top end closure annulus 13 and the liquidremoved from the `gas and returned Ito the evaporator in the separator4.

The above construction gives a high rate of heat transfer and a largeoutput of `ice per square foot of ice freezing surface. The ice is drywhen removed from the freezing surface and remains dry to the storagebin 2.

Obviously changes may be made in the forms, dimensions and arrangementsof the parts of my invention without departing from the principlethereof, the above setting forth only preferred forms of embodiment ofmy invention.

I claim:

l. An ice making machine comprising .an upright first substantiallycylindrical shell for forming ice on the inner surface thereof; anupright second substantially cylindrical shell surrounding said firstshell, the diameter of the inner surface of the first shell being aplurality of times greater than the distance between the first andsecond shells; top and bottom closure annuli, each connected betweensaid shells andJ spacing apart said shells, said shells and said annuliforming a closed annular space; an upright substantially cylindricalbaille shell disposed between and spaced from said first and secondshells and having passageways between its end portions and said annuli,and forming interconnected ascending and descending passageways forcirculation of liquid refrigerant, wherein liquid refrigerant travelsupwardly between said first shell and said baille, thence transverselyoutwardly in said passageway at an upper end portion of said baille,thence downwardly between said baffle and said second shell, and thencetransversely inwardly in said passageway at said lower end portion ofsaid baille; means supplying liquid refrigerant to one of said ascendingand descending passageways; a gas separator chamber having an inlet incommunication with said ascending and descending passageways and at anupper end portion thereof, having a vertically disposed curvilinearbaille therein to direct the refrigerant fluid from the inlet in ahelical path to separate out the liquid component of the fluid, having agas discharge outlet means, and having a liquid refrigerant dischargecommunica-ting with one of said ascending and descending passageways andat a location below the inlet to the gas separator; and means supplyingwater to the inner surface of said first shell to be frozen into ice.

2. An ice making machine comprising an upright tlrst substantiallycylindrical shell for forming ice on the inner surface thereof; anupright second substantially cylindrical shell surrounding said firstshell, the diameter of the inner surface of the first shell being aplurality of times greater than the distance between the first andsecond shell, facilitating mechanical ice removal; top and bottomclosure annuli, each connected between said shells, and spacing apartsaid shells, said shells and said annuli forming a closed unrestrictedannular chamber; an upright substantially cylindrical baille shelldisposed in said annular chamber, spaced between said first and secondshells, and having transverse passageways at its end portions adjacentsaid annuli, and forming directly interconnected ascending, transverse,descending, and transverse passageways for the circulation of liquidrefrigerant, wherein liquid refrigerant circulates upwardly between saidrst shell and said baille, thence transversely outwardly in the uppertransverse passageway adjacent the upper end portion of said baille,thence downwardly between said baille and said second shell, and thencetransversely inwardly in said transverse passageway adjacent the lowerend portion of said baille; gas-liquid discharge means connected withsaid annular chamber and at substantially the vertical level of the topend portion of said baille; and means providing a refrigerant liquidlevel in said annular chamber with liquid refrigerant ilooding throughthe transverse passageway at the top end portion of said baille and withgas and entrained liquid refrigerant delivered to said gas-liquiddischarge means.

3. An ice making machine comprising an upright ilrst substantiallycylindrical shell for forming ice on the inner surface thereof; anupright second substantially cylindrical shell surrounding and spacedfrom said iirst shell, the diameter of the inner surface of the ilrstshell being a plurality of times greater than the distance between thefirst and second shell, facilitating mechanical ice removal; top andbottom closure annuli, each connected between said shells, said shellsand said annuli forming a closed unrestricted annular chamber; anupright substantially cylindrical baille shell disposed in said annularchamber, spaced between said ilrst and second shells, and havingtransverse passageways at its end portions, and forming directlyinterconnected ascending, transverse, descending, and transversepassageways for the circulation of liquid refrigerant, wherein liquidrefrigerant circulates upwardly between said iirst shell and saidbaille, thence transversely outwardly in the upper transverse passagewayadjacent the upper end portion of said baille, thence downwardly betweensaid baille and said second shell, and thence transversely inwardly insaid transverse passage way adjacent the lower end portion of saidbaille; a gasliquid separator chamber means connected with said annularchamber and having a substantial portion of its chamber above thevertical level of the top end portion of said baille; and meansproviding a refrigerant liquid level in said annular chamber with liquidrefrigerant flooding through the transverse passageway at the top endportion of said baille and with gas and entrained liquid refrigerantdelivered to said gas-liquid separator chamber means.

4. An ice making machine comprising an upright ilrst substantiallycylindrical shell for forming ice on the inner surface thereof; anupright second substantially cylindrical shell surrounding said rstshell, the diameter of the inner surface of the first shell being aplurality of times greater than the distance between the iirst andsecond shell, facilitating mechanical ice removal; top and bottomclosure annuli, each connected between said shells, said shells and saidannuli forming a closed unrestricted annular chamber; an uprightsubstantially cylindrical baille shell disposed in said annular chamber,spaced between said first and second shells, and having transversepassageways at its end portions, and forming directly interconnectedascending, transverse, descending, and transverse passageways for thecirculation of liquid refrigerant, wherein liquid refrigerant circulatesupwardly between said ilrst shell and said baille, thence transverselyoutwardly in the upper transverse passageway adjacent the upper endportion of said baille, thence downwardly between said baille and saidsecond shell, and thence transversely inwardly in said transversepassageway adjacent the lower end portion of said bafile; gasliquiddischarge means connected with said annular chamber and at substantiallythe vertical level of the top end portion of said baille; and meansproviding a refrigerant liquid level in said annular chamber with liquidrefrigerant ilooding through the transverse passageway at the top endportion of said baille and with gas and entrained liquid refrigerantdelivered to said gas-liquid discharge means.

References Cited in the ille of this patent UNITED STATES PATENTS1,635,058 Potter July 5, 1927 2,042,394 Gay May 26, 1936 2,154,905 KagiApr. 18, 1939 2,156,426 Brown May 2, 1939 2,387,899 Gruner Oct. 30, 19452,462,329 Mojonnier Feb. 22, 1949 2,512,869 McBroom .Tune 27, 19502,548,441 Morrison Apr. 10, 1951 2,703,969 Lindsey Mar. 15, 19552,712,734 Lees July 12, 1955

